Black & Decker Mfg. Co. v. Baltimore Truck Tire Serv. Corp.

• Decision Date: 08 April 1930
• Docket Number: No. 2889.,2889.
• Citation: 40 F.2d 910
• Parties: BLACK & DECKER MFG. CO. et al. v. BALTIMORE TRUCK TIRE SERVICE CORPORATION.
• Court: U.S. Court of Appeals — Fourth Circuit

40 F.2d 910 (1930)

BLACK & DECKER MFG. CO. et al. v. BALTIMORE TRUCK TIRE SERVICE CORPORATION.

No. 2889.

Circuit Court of Appeals, Fourth Circuit.

April 8, 1930.

Edwin F. Samuels, of Baltimore, Md., for appellants.

John C. Kerr, of New York City (Cooper, Kerr & Dunham, of New York City, and Venable, Baetjer & Howard, of Baltimore, Md., on the brief), for appellee.

Before WADDILL and PARKER, Circuit Judges, and McDOWELL, District Judge.

PARKER, Circuit Judge.

This suit was instituted in the court below to enjoin infringement of patent No. 1,458,920, issued to Frederick J. Troll. Complainants were the assignee of the patent and the exclusive licensee thereunder. The defendant was a tire service corporation of Baltimore which was using one of the infringing devices manufactured by the E. & T. Fairbanks Company. That company defended the suit. From a decree holding one of the claims relied on to be invalid and the others not to be infringed, complainants have appealed.

The patent in suit covers a "road bearing pressure meter" or small platform scale, designed for ascertaining the wheel load on motor vehicles. It is used by traffic officials for the purpose of detecting violations of state laws against the overloading of vehicles driven on the public highways and by tire manufacturers and dealers for ascertaining the wheel load on tires on motor vehicles and thus determining the proper size of tires to use. It has three distinguishing characteristics: (1) It is manually portable, i. e., it is so light that it can be handled without difficulty by one man; (2) it is low and flat with sloping approaches from two directions, and for this reason peculiarly adapted for use in weighing automobile trucks, which can be driven on and off of it without difficulty; and (3) although small and light, it is equipped with a weighing device which registers with substantial accuracy weights as great as 20,000 pounds. It is thus described together with the purpose for which it was intended in the application for the patent:

"The destruction of road surfaces incident to heavy traffic, particularly motor vehicle traffic, has resulted in legislation limiting the weight per unit of tire width which may be carried on road vehicles. The territory in which such legislation is enforced is being rapidly extended, though the adoption of such laws has been retarded on account of the difficulties incident to inspection. Where violation of the law in this regard is merely suspected, to compel the driver of a heavily loaded vehicle to depart from his route, in order that the vehicle and load might be weighed, would work extreme hardship and often injustice.

"The present invention is intended to overcome this difficulty by providing a convenient portable device for determining the bearing pressure on tires. This apparatus may be used either by the operator of the vehicle to avoid violation of the law, or by traffic officers and the like to detect such violations, the same being adapted to be carried conveniently by a traffic officer in his machine, and of such weight that it can be removed from the machine and handled and arranged for operation by one man. It is also comparatively inexpensive, so that it may logically be a part of the equipment, as are the speedometer, and other testing and indicating devices, as air gauges, jacks, etc.

"The apparatus consists of a portable yielding support, having means for indicating the weight borne by the support, the same being of small dimensions and low or flat, and adapted to be placed beneath any one of the wheels of a road vehicle to determine the weight borne by it. As the most convenient means of getting it beneath the wheel is to place it in the road and run the wheel on to it, a run-way is a convenient, if not a necessary part of the equipment, and the run-way or run-ways are preferably made detachable, so that the weighing member or support may be handled separately from the run-way and if desired, used separately therefrom. In the accompanying drawing I have illustrated in detail a portable road-pressure meter, combining my invention in its preferred form.

"As a means particularly adapted to the accurate measurement of the heavy weights which must be dealt with in this connection, there is shown in connection with the invention in its preferred form a coil or other arrangement of flexible tubing, containing fluid which operates in connection with a fluid pressure gauge, to determine the pressure on the yielding support, the coil of tubing being so placed that the pressure of the yielding member is applied directly to its lateral surfaces. * * *

"By using my road bearing meters in pairs spaced apart by the width of the tread so that the wheels may be run on them in pairs, it is made possible to read all four wheels correctly with comparatively little effort or a maximum reading may be obtained by merely running over the meters thus placed."

In the commercial scale manufactured under the patent, the runways are not detachable but are made as a part of the framework of the scale. The flexible tubing suggested as a part of the weighing device is not used, but the weight on the platform is measured by means of levers bearing upon a flexible diaphragm over a chamber filled with oil and a gauge which registers the pressure of the oil. Of the claims of the patent relied on, the following, 2, 5, and 15, may be taken as typical:

"2. A tire bearing pressure meter, comprising a manually portable apparatus including a base, a platform member and a guide therefor, a resilient member of sufficient resistance to carry a wheel of a loaded truck supporting the platform member, said apparatus being of extremely short vertical dimension and having an inclined portion leading to the platform so that the wheel of a truck can be run onto it without difficulty when it is placed in the roadway and means for indicating the pressure on said resilient member."

"5. A bearing pressure meter for roads, comprising a manually portable apparatus, of short vertical dimension having a yielding support for a vehicle wheel the same being of width only sufficient to receive and support a single wheel and means for indicating the pressure on the support."

"15. A method of determining wheel pressure of road vehicles while the vehicles are on the road, which consists in placing a plurality of manually portable independent weighing units on the roadway in the path of the wheels, spacing them apart to correspond to the tread, running the wheels onto the weighing units and reading the respective weighing units."

As stated in the application, the patent was developed in response to the need for means of weighing trucks which were suspected of violating the laws against overloading. With the increase of automobile traffic, the problem of overloading, with consequent damage to the highways, had become a very real one. On one road in Maryland, the damage done in a single year amounted to approximately $600,000, whereas the estimated saving to private persons as a result of the overloading did not exceed $15,000. Laws against overloading were enacted; but these were hard to enforce because of the difficulty in proving the weight of the loads. At first, platform scales of the ordinary type were installed for this purpose at various points on the roads. These, however, were expensive and ineffective. Violators of the law soon learned of their location and avoided them. A portable weighing jack was then used for a while, but this, too, failed to solve the problem. It was difficult to obtain accurate results with it, and its use consumed so much time that blocking of traffic frequently resulted. The small platform scale covered by the patent exactly met the situation, and quickly came into use in thirty-six states of the Union and sixteen foreign countries for testing loads on highways. It came immediately into use also by tire dealers and manufacturers in their testing of tires.

The development of the infringing scale used by defendant resulted from the effort of the licensee under the patent to make a sale to the Firestone Tire & Rubber Company for the latter purpose. That company and the licensee were unable to agree on a price, whereupon the Firestone Company entered into negotiations with the E. & T. Fairbanks Company, which has for many years been engaged in the building of scales, to manufacture a similar scale for it. The Fairbanks Company's engineer, with one of the patented scales before him, was able to build one very similar to it, except that the Fairbanks scale was a little larger and a little heavier and substituted a system of levers with a beam and poise as the weighing device for the oil pressure gauge. It not only looked like the scale of the patent, but was designed for the same purpose and accomplished the same result in practically the same way. The change in the weighing device was but the substitution of a well recognized equivalent.

We entertain no doubt that Troll's scale was patentable. It is true that all of the ideas which it embodied were old; but their combination resulted in a product which was entirely new. It was old to determine the weight of a vehicle by weighing each of its wheels separately. The platform was old, and so also was the sloping approach to the platform. And there was nothing new, of course, in measuring weight by pressure on liquid with the use of a Bourdon tube and gauge. But it was new to combine all of these features in a scale so small that it could be carried about by a single man, but with a capacity so great that it could be used to weigh a load of 80,000 pounds. It was not a mere...